bobbycloud
Member
Posts: 53
home town/country: Odessa, TX United States
time zone gmt +/-: -6 Central
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Post by bobbycloud on Apr 28, 2016 17:16:05 GMT
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Post by Rick in NWArk on Apr 28, 2016 18:09:21 GMT
Bobby,
Are you using your 120APO or your 12" SCT? I'm assuming based upon what I am seeing the latter. I'm not an expert at the Universe, but to me it looks like your focal reduction is hurting - I see star stretching at the edges and vignetting (the circle where its black outside).
Your 12" has a really long focal length at > 3000mm which is a really small field of view. What focal reduction are you using?
--Rick
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bobbycloud
Member
Posts: 53
home town/country: Odessa, TX United States
time zone gmt +/-: -6 Central
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Post by bobbycloud on Apr 28, 2016 19:24:54 GMT
Rick These photos are from the 12" Meade SCT LX850 ACF f/8, the focal reducer is the Mallincam 0.5x focal reducer. Rick I also have a spacer installed on these photos Here is what the website indicates on the reducer/spacer effects- Possibility of to much reduction on the f/8???
• 0.5X T-mount focal reducer
The optional 0.5X focal reducer is a recommended accessory when using the
Universe on a telescope with a long focal length and/or a high F-ratio, such as F8 or
greater. A long focal length yields a relatively small field-of-view. The 0.5X focal
reducer essentially cuts the telescope’s focal length in half and provides a field-of-view
that is twice as large in both length and width. It also reduces the F-ratio by a factor of
two. For example, it makes a relatively slow F10 optical system perform like a much
faster F5 configuration. This cuts the exposure time down by a factor of four. A properly
exposed 8-minute image taken through an F10 telescope would only require a 2-minute
exposure to achieve the same level of brightness using the focal reducer! And the sky
area covered in the image would be four times greater! A highly recommended accessory
to increase the near-live viewing experience!
• Focal reducer spacer
This is used to increase the focal reduction factor even further when using the 0.5X
focal reducer. The degree of reduction varies with the telescope type.
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Post by Rick in NWArk on Apr 28, 2016 21:57:14 GMT
Bobby,
I have used an f/8 system with the .5x reducer, but that was going from about an 1600 focal length versus your 3000. Also, I was going to a 1/2" chip versus the larger Universe chip. I should add that I also moved to use only the larger part of that MFR reducer (.7x) a lot, too. I just wanted some objects to be a bit bigger.
From these objects you've posted, you have plenty of room for a bigger field of view. Maybe you should test it without the spacer at least, if not just going with one part of the MFR5.
Part of the challenge of Video Astronomy is coming up with the combinations where you find that sweet spot. I am bad at taking notes and often find myself chasing the combo that I used last time that gave me good results, hahaha!
--Rick
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bobbycloud
Member
Posts: 53
home town/country: Odessa, TX United States
time zone gmt +/-: -6 Central
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Post by bobbycloud on Apr 28, 2016 22:18:04 GMT
Thanks for the info Rick, I too am bad about remembering what I did the night before even taking notes which make no sense two days later. I will trudge on, I really enjoy looking and imagining the skies great therapy for a newly retired, slightly worn out old man. I enjoy sharing my sights with family and friends not wanting to be a professional just knowledgeable. Thanks again.
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Post by davy on Apr 28, 2016 23:24:24 GMT
Hi Bobby,just because you dont get up to go to work everyday ,does not mean your old or retired..it's when you let the grey matter retire you get old ,lol. Know the feeling about not wanting to be a professional,,I was asked one night,my partner pointed to a bright object in the night sky and asked,,what is that called...reply..a star,,, I bought a goto scope so I didnt need to learn constellations ect,I just want to look through a scope and go WOW,,then I go and check on Google sky maps,,that was a few years back,,,and im still the same...its a star,,,,jupiter was even a star one night lol..its a hobby ,its ment to be fun,,I like the techy side and thinking up new was to do it...have to,,,weather is usually ...poor..me being diplomatic. :-)
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Post by Rick in NWArk on Apr 29, 2016 14:38:42 GMT
Wish you were a tad closer, Bobby, it'd be fun to collaborate and have a couple setups going and just spend a night messing about.
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bobbycloud
Member
Posts: 53
home town/country: Odessa, TX United States
time zone gmt +/-: -6 Central
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Post by bobbycloud on Apr 29, 2016 15:36:10 GMT
Rick been here so long and it takes a good 12-13 hrs just to get to the east side of Texas/Houston area. I might get to a few gatherings/Star Parties before I get too old. Was hoping to view last night but the weather was unstable and windy. I think I will mount the 120 APO on the AVX and see what happens?
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Post by Rick in NWArk on Apr 29, 2016 15:47:55 GMT
I think the AVX is a pretty good mount, especially for wide field. My problems have come when I've put the 8" F/6 RC on there. I've heard good things about the Eldorado TX Star Party and it's only 2 1/2 hours from you. eldoradostarparty.org/
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